U.S. President Donald Trump has thanked Russia, Iran and Syria for slowing down their operation targeting Idlib province, while also thanking Turkey for helping to negotiate restraint.

Trump told on Sept. 26 the United Nations Security Council that the "Syrian regime's butchery is enabled by Russia and Iran" during a session devoted to discussing non-proliferation of weapons of mass destruction, before switching to a more positive note.

"I want to thank Iran, Russia and Syria for --at my very strong urgent and request-- substantially slowing down their attack on Idlib province and three million people who live there in order to get 35,000 targeted terrorists. Get the terrorists but I hope the restraint continues. The world is watching," he said.

"Thank you also to Turkey for helping to negotiate restraint. Anything the U.S.A. can do to help resolve this problem in order to save perhaps even hundreds of thousands of lives, maybe more, we are willing and able. We are available to help," Trump added.

He addressed the recent decision of Moscow to strike a deal with Turkish AKP government to avoid a full-scale military operation by the Syrian army against the jihadist-held city of Idlib.

The province in the northwest of Syria is the last remaining stronghold of armed groups in the country, including Nusra Front terrorist organization. Idlib's dominant terrorist faction is Tahrir al-Sham, a jihadist alliance spearheaded by al Qaeda's official affiliate in Syria, the Nusra Front.